This invention relates to fluid joints and more particularly to fluid joints utilizing a crimped ferrule to facilitate the formation of the joint.
It is often necessary, for example in the assembly of a motor vehicle to provide a fluid joint between a relatively rigid tube and a relatively flexible hose. It is common practice, for example, to form such a joint by the use of a ferrule coacting with an upset or bead formed on the tube at a location spaced from a free end of the tube to define a pilot portion between the bead and the tube free end for insertion into the free end of the hose. The joint is formed by inserting the pilot portion of the tube into the free end of the hose and crimping the ferrule at one end to the free end of the hose and at its other end to the pilot portion of the tube proximate the bead. Whereas this arrangement provides satisfactory fluid connection between the tube and the hose there is a tendency for galvanic action to occur between the dissimilar metallic materials of the ferrule and the tube at the interface of the ferrule and the bead with the result that corrosion may form at this location with consequent degradation of the joint.
This invention is directed to the provision of an improved fluid joint;
More particularly, this invention is directed to discouraging corrosion in a fluid joint of the type employing dissimilar metallic members.
The invention concerns a fluid joint of the type including a generally rigid metallic tube having an annular bead spaced from a free end of the tube to define a pilot portion between the bead and the tube free end, a generally flexible hose sized to fit at a free end thereof over the tube pilot portion, and a metallic ferrule crimped at a first end thereof over the hose free end and crimped at a second end thereof over the tube pilot portion.
According to the invention, the joint further includes an elastomeric ring positioned in surrounding relation to the tube pilot portion between the bead and the second end of the ferrule. The elastomeric ring provides a seal between the ferrule and the bead to keep out contaminants such as water, salt, or dirt that may promote corrosion at the interface between the ferrule and the bead. The ring further provides isolation between the ferrule and the bead.
The invention further provides a method of providing a fluid joint between a generally rigid metallic tube and a generally flexible hose.
According to the invention methodology, an annular bead is provided on the tube spaced from a free end of the tube to define a pilot portion between the bead and the tube free end; a metallic ferrule is provided having first and second ends; the first end of the ferrule is crimped over the free end of the hose; an elastomeric ring is provided; the ring is positioned in surrounding relation to the tube pilot portion; the tube pilot portion is inserted into the second end of the ferrule and into the free end of the hose to press the ring against the bead; and the second end of the ferrule is crimped to the tube pilot portion proximate the bead to trap the ring between the second end of the ferrule and the bead. This simple methodology provides a joint in which contamination or corrosion is discouraged at the interface of the ferrule and the bead.
In the disclosed embodiment of the invention, the step of positioning the ring in surrounding relation to the pilot portion includes positioning the ring against the bead. Positioning the ring against the bead prior to insertion of the tube pilot portion into the second end of the ferrule insures proper positioning of the ring in the final configuration of the joint.
Other objects, advantages and applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.